Tubular perforator.



A. DOM.

TUBULAR PERFORATOR.

APPLICATION FILED JUNE 1. 1915.

Patented Sept. 24,1918.

anua /wto'a ran erase rear on o,

ALEXANDER DOM, OF CINCINNATI, OHIO, ASSIGNOR TO THE SAMUEL TAT'UM COMPANY, OF CINCINNATI, OHIO, A CORFORATION OF OHIO.

TUBUIJAR PERFORATOR.

To all whom it may concern:

Be it knownthat I, ALEXANDER DOM, a

I citizen of the United States, and residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented a newand useful Tubular Perforator, of which the following specification is a full disclosure.

This invention deals with a tubular paper perforator of the type disclosed in United States Patent No. 808,408, issued to Walter. Sparks, Dec. 26, 1905, and it consists in improving the same by providing a compound relief in the base of the cutter for the purpose of reducingthe friction of the discharging paper waste. The core provides an inner delivery passage with a relief from one end to'the other, and of different degrees at different portions of its length, and

with a cutting edge beveled in a reverse direction. The portion of the bore immediately from the cutting edge is formed with a sharp angle or degree of taper for quickly reducing the friction of the waste comparative to the remaining portion of the bore which assumes a more gradual taper to a given length of shank without jeopardizing the intensity of the tool.

In the annexed drawing,

Figure 1 shows a longitudinal cross section of the improved drill punch or perforator of enlarged size.,;

Fig. 2 is a bottom plan view thereof.

The perforator conslsts of a tubular shank 1, preferably having an enlarged head 2,

whereby.it may be held in a rotating chuck. The shank and head are provided with a longitudinal bore as a delivery passage for the chips or waste and possessing a tapering relief from the mouth to the exit end, pre senting the smaller diameter at the mouth for a free discharge of the chips. The mouth end has the bevel of the cutting edge 3, extending outwardly to the outer diameter of the shank in a reverse direction to the relief taper .of the delivery passage. This bevel approximates sixty degrees.

The paper chips obviously are compressed, since the bore at the oint 4 at its smallest diameter is apprecia ly smaller than the outside diameter of the tube, and will ofier a certain resistance to passage therethrough owing to friction. A drill of 13/32 (.4062-5") outside diameterproportions a bore diame er at the mo h approximating sistance to their discharge.

,28$ )25, -a difierence of .1170 between the inside and .outside diameters.

This variation produces the proper cup- Specification of Letters Patent. Patented SQEPt. 24:, T9113. I. Application filed June 7, i915. Serial in. 32,52 i

ping of the waste or chips as they are compressed through the mouth, and to prevent the friction unduly cumulating and the chips blocking the passage I provide a sudden relief by a comparative sharp degree of taper for a limited portion of the length of the bore immediate of the cutting edge bevel.' This permits the chip 'to release quickly, accommodating for the degrees of expansion or spreading with the resulting pressure aiding to the continuous movement ofthe mass through the passage, and enable them to readily assume their set condition,

after which they offer substantially no re- From such sharp tapering region or quick relieving length, the bore continues toward the head With a more gradually tapering portion, and in the head 2 the bore is cylindrical and approximately-of the outside diameter of the shank.

The portion or sharp tapering relief for dimensioned above in length is about .5955, and a taper of about 5 while the graduregion a, defining the the size of drill ally tapering portion 6 has a taper equaling I i about 21 minutes for its length.

The drill may be used in any .manner customary, as by a power or drill press, whereby it is rotated 'at a requisite speed, and depressed to feed it through thepaper with accuracy and despatch. The compound bore relief materally reduces the frictional resistance of the discharging waste, permitting the tool to be fed at an increased speed without injury, over a tool of the art provided with a single continuous degree of taper, which distinguishing aspect, however,"

is inherently containedin my drill.

Having described my invent1on,I clalm 1. A perforator having a tubular shank of uniform external diame'ter,tand with a cutting edge formed on the extremity, the bore of the shank providing an inner delivery passage having relative different degrees of taper for different portions of its length, with the portion immedlate the cutting edge dominating 111 degree.

2. A perforator having a tubular shank and a cutting edge formed on the extremity,

and the bore of the shank tapering outwardly from the cutting end to the other in relative my name, as attested by the two subscribing differfint degrees for difiel ent glortioniq1 of its Witnesses. lengt With t e portion imme iate t e cutting edge dominating in degree, and with ALEXANDER 5 the bevel of the cutting edge in 2t reverse Witnesses:

direction. CLARENCE B; FOSTER,

In Witness whereof I hereunto subscribe L. A. BECK. 

